In order to investigate the experimental transfer of Paragonimus westermani from rodents to rodents following subcutaneous and intraperitoneal routes, 13 rats and 23 mice were inoculated with a total of 115 (1 mature and 114 immature) worms of P. westermani subcutaneously and intraperitoneally. The age of worms before transfer was 25–193 days. The transfer was performed immediately after worm collection from rodents which were killed at various intervals from 4 to 144 days after infection. The location, development and size of worms were recorded. An infection rate of 58% (or 21/36) was demonstrated in rodents after experimental transfer of P. westermani by intraperitoneal and subcutaneous routes. Twenty-seven worms were recovered, giving a worm recovery rate of 23.5%. The rate was significantly higher by the subcutaneous route (34.8%) than by the intraperitoneal route (20.7%) but no difference was found between mice (23.9%) and rats (23.0%). The sizes of worms in the abdominal cavity, pleural cavity and thoracic muscles of mice, and in the leg muscles of rats were much less than in the pleural cavity and lung cysts of rats. A mature worm (7×5 mm) and numerous eggs were found in the uterus and pleural cavity of one rat. It is evidence that these rodents are unfavourable definitive hosts of P. westermani, because the worm size, infectivity, maturation and egg production are usually very low. However, the worms are usually widely distributed in their rodent hosts and remain small in size for a long period. Therefore, these rodents are good paratenic hosts for P. westermani and can play an important role in infecting cats and dogs with P. westermani in the laboratory.

The resistance to infection by Ostertagia spp. of three groups of lactating ewes was compared with an unbred control group. Group 1 was fed a full diet of hay and a concentrate ration ad lib. Groups 2 and 3 were fed the same quantitatively inadequate diet and in addition group 3 received daily injections of thyroxine sodium. All the animals were infected regularly with Ostertagia larvae and killed 6 weeks after lambing.

While the unbred sheep were highly resistant, all three groups of lactating ewes carried significant numbers of worms. Group 2 and 3 had significantly more than group 1, the additional worms being present as adults. The effect of hyperthyroidism in group 3 was not significant.

It is concluded that the immuno-suppressant effect of lactation is probably not due to protein depletion although the latter may be an important secondary factor.

Echinococcus granulosus sensu stricto is regarded to have the highest zoonotic potential of all Echinococcus taxa. Globally, human infection due to this species constitutes over 88.44% of the total cystic echinococcosis (CE) burden. Here, we report a CE infection in a Nigerian camel caused by E. granulosus G1 genotype. To the best of our knowledge, this report is the first encounter of the G1 genotype in the West Africa sub-region where the G6 genotype is reportedly prevalent, suggesting that the epidemiology of this highly zoonotic group could have a wider host range and distribution in the sub-region, and emphasizes the need for further investigation into the genetic diversity of Echinococcus spp. in Nigeria and across the sub-region.

Many temperate freshwater habitats are at risk for contamination by run-off associated with the application of road de-icing salts. Elevated salinity can have various detrimental effects on freshwater organisms, including greater susceptibility to infection by parasites and pathogens. However, to better understand the net effects of road salt exposure on host–parasite dynamics, it is necessary to consider the impacts on free-living parasite infectious stages, such as the motile aquatic cercariae of trematodes. Here, we examined the longevity and activity of cercariae from four different freshwater trematodes (Ribeiroia ondatrae, Echinostoma sp., Cephalogonimus sp. and an unidentified strigeid-type) that were exposed to road salt at five different environmentally relevant concentrations (160, 360, 560, 760 and 960 mg/ml of sodium chloride). Exposure to road salt had minimal detrimental effects, with cercariae activity and survival often greatest at intermediate concentrations. Only the cercariae of Cephalogonimus sp. showed reduced longevity at the highest salt concentration, with those of both R. ondatrae and the unidentified strigeid-type exhibiting diminished activity, indicating interspecific variation in response. Importantly, cercariae seem to be relatively unaffected by salt concentrations known to increase infection susceptibility in some of their hosts. More studies will be needed to examine this potential dichotomy in road salt effects between hosts and trematodes, including influences on parasite infectivity.

In this study we described two new trematode species, Lecithostaphylus halongi n. sp. (Zoogonidae, Lecithostaphylinae) and Gymnotergestia strongyluri n. sp. (Fellodistomidae, Tergestiinae), on the basis of morphological and molecular data. Adult worms of these two species were collected from, respectively, Hemiramphus spp. (Hemiramphidae) and Strongylura strongylura (Belonidae) caught in the coastal waters of Vietnam. Adult worms of L. halongi n. sp. are morphologically close to Lecithostaphylus gibsoni Cribb, Bray & Barker, 1992 ex Abudefduf whitleyi from Heron Island and Lecithostaphylus depauperati Yamaguti, 1970 ex Hemiramphus depauperatus from Hawaii, but differ from these species in having a larger cirrus sac and a different arrangement of vitelline fields. They also differ from Lecithostaphylus brayi Cabañas-Granillo, Solórzano-García, Mendoza-Garfias & Pérez-Ponce de León, 2020 in the 28S ribosomal DNA (rDNA) sequence data at the interspecific level. Adult worms of G. strongyluri n. sp. ex S. strongylura are morphologically similar to Gymnotergestia chaetodipteri, the only previously known species of this genus, described from Chaetodipterus faber in Jamaica. The new species differs from G. chaetodipteri in body shape, testicular arrangement and the size of the pharynx and eggs. The 28S rDNA-based phylogenetic analysis indicates that G. strongyluri n. sp. is closely related to Tergestia spp., rendering Tergestia paraphyletic. Genetic divergence values between G. strongyluri n. sp. and Tergestia spp. are similar to those among species in the genera Tergestia, Steringophorus and Proctoeces. Our molecular results indicate that G. strongyluri n. sp. and Tergestia spp. may belong the same genus, but additional molecular data are needed for the final conclusion.

Twenty-three (9%) of 255 domesticated dogs surveyed in Lahore, West Pakistan, were blood positive for microfilariae. Twenty-one (8·2%) had either pure or mixed infections with Acanthocheilonema dracunculoides. Dirofilaria repens microfilariae were present in 4 dogs and one had Dirofilaria immitis microfilariae. A single adult A. dracunculoides was found from the hind leg of an autopsied dog with A. dracunculoides microfilariae. Microfilariae had a diurnal periodicity in this animal. There is only one previous documented report of A. dracunculoides adult worms from a dog in the Indian subcontinent, but it is possible that microfilariae earlier described from India under other names may also have represented this species.

Filariasis is very common in tropical countries. It is endemic in the coastal areas of India. We report four cases of haematological malignancy where peripheral blood and bone marrow smears did not show any microfilariae but conventional cytogenetic preparations from all the four cases showed the presence of parasites. Their morphology confirmed the diagnosis of all cases as bancroftian filariasis. Therefore all types of cytogenetic preparations should be screened carefully in the endemic areas along the coastal zones of India for the presence of this parasite.

1. An Athesmia sp. from two species of jackals (Canis adustus Sundervall, 1846, and Canis mesomelas Schreber, 1775) in northern Tanzania is described.

2. While considerable variation in size and internal morphology was observed, these differences do not appear to be significant.

3. There being no constant morphological features to establish a new species, these specimens are for the present considered to be A.foxi Goldberger and Crane, 1911.

4. The difficulties in the identification of Athesmia are discussed and the present position in the genus briefly reviewed.

5. Histopathological studies were carried out with negative results and reference is made to other reports of such studies in the literature.

Nematodes of the family Thelastomatidae are parasitic in the alimentary tract of many arthropods, including Periplaneta americana L. In Meerut, Uttar Pradesh, India, two nematode species, namely Hammerschmidtiella indicus and Thelastoma icemi, belonging to this family have been reported. In the present study, the molecular phylogeny of these two nematode species was derived using small subunit (18S) sequence and secondary-structure analyses. The small subunit sequence analyses were carried out to explore the validation and systematics of these species. Phylogenetic analyses were performed for primary sequence data as well as using neighbour-joining and maximum-parsimony approaches. In contrast, the inferred secondary structures for the two species, using free-energy modelling, showed structural identities. As well as this, motif sequences were also found to be a promising tool for nematode species identification. The study provides molecular characterization based on primary sequence data of the 18S ribosomal DNA region of the nematodes along with secondary-structure data and motif sequences for inferences at higher taxonomic levels.

Uptake and serosal transfer of the vitamins thiamine, riboflavin and folic acid have been studied in vivo in normal and parasitized rats infected with Hymenolepis diminuta (Cestoda).

Regional differences in intestinal uptake of all three vitamins in both uninfected and parasitized animals were not statistically significant.

In the parasitized intestine mucosal uptake and serosal transfer of thiamine were significantly inhibited, with increased mucosal accumulation of the vitamin as luminal thiamine concentration increased.

Apparent increased riboflavin mucosal uptake in parasitized animals, was not matched by the reduced serosal transfer, suggesting adsorption of the vitamin in the unstirred aqueous layers.

Mucosal uptake of folic acid increased in the parasitized gut; serosal transfer and mucosal accumulation were not affected.

These results, indicating vitamin malabsorption associated with infection by H. diminuta, are consistent with the parasite inhibiting mucosal passive transport mechanisms. This conclusion is supported by the changes in net water fluxes associated with vitamin uptake in the parasitized intestine.

During the tour in Kashmir, two males and four females of the species to be described were collected from the vicinity of the heart and the body cavity of the white cheeked Bulbul, Molpastes leucogenys leucogenys.

These are rather slender worms with attenuated anterior ends. The posterior ends are twisted into 2–3 coils. The cuticle is thin, smooth, nonstriated, but richly furnished with bosses throughout the length of the body.

In the acanthocephalan Neoechinorhynchus crassus five embryonic envelopes have been identified, including four, which are similar to those in previously studied acanthocephalans and a supplementary one, located between the outer and the second envelopes, which is characteristic of only a few Eoacanthocephala. The terminology of the envelopes in relation to their origin and possible function is discussed.

RAPD technique was used to differentiate individuals of Anisakis simplex obtained from Merluccius merluccius, Phycis blennoides, Conger conger and Lepidorhombus boscii, from the North Atlantic Ocean. The amplification patterns of the host DNA controls were markedly different from those obtained for the parasitic material. No variation within the same host was detected. The amplification patterns for larvae obtained from fish of the same genus were somewhat different. The amplification patterns of A. simplex isolates from M. merluccius, P. blennoides, C. conger and L. boscii, were different. These results suggest the possible existence of two populations with a considerable high genetic variability and a different adaptation to different host species.

Homogenates of the metacercariae of Clinostomum complanatum showed two peaks for the hydrolysis of p-nitrophenyl phosphate at pH 4·5–5·0 and 11·0; specific activity at pH 5·0 was 0·017 µmol p-nitrophenol/mg protein/min and 0·0049 µmol p-nitrophenol/mg protein/min at pH 11·0 at 37°C. Maximal activities of acid and alkaline phosphatases were observed at 50° and 40°C respectively. Both enzymes reached maximal rates after 50 min of incubation. Linearity in enzyme activity was noticed with increasing homogenate concentrations for both enzymes. The Km for p-nitrophenyl phosphate was 1·1 mM with a Vmax of 0·018 units/mg protein for acid phosphatase and 1·6 mM with a Vmax of 0·0052 units/mg protein for alkaline phosphatase. Sodium arsenate and sodium fluoride inhibit and Mg++ and Co++ stimulate both enzymes. Polyacrylamide gel electrophoresis showed one cathodic band each for both the enzymes.

A post-parturient rise in worm egg count was seen in ewes which lambed in the autumn following ovulation induced by hormone treatment. Similarly treated ewes in the same flock which proved to be barren showed only a slight increase in egg count. There were indications that hormone treatment may be associated with egg count rises which differ in intensity and duration from those reported in ewes which ovulate spontaneously.

The rat tapeworm Hymenolepis diminuta can bioconcentrate several elements to conspicuously higher concentrations than tissues of their definitive host. The main aim of this study was to locate parts of the tapeworm into which lead, cadmium, zinc, copper, manganese and iron are accumulated. Male Wistar rats were experimentally infected with H. diminuta and worms were exposed to two different forms of lead for 6 weeks through the oral exposure of their rat hosts. After the exposure period, the element levels were determined in the posterior and anterior proglottids of the tapeworm. In all cases, lead concentrations were higher in the anterior parts than the posterior parts. Concentrations of cadmium, copper, iron, manganese and zinc were also significantly higher in the anterior parts. Zinc concentrations showed an opposite trend, with higher zinc levels detected in the posterior part of the strobila, in the control group. The present study demonstrates that risk and essential elements are accumulated mainly into the anterior part of H. diminuta.

1. A precipitate was formed at the oral opening, excretory pore and anal opening of the fourth stage juveniles of O. columbianum in the presence of immune serum in vitro, causing their immobilisation and subsequent death in large numbers. The precipitates failed to appear on these juveniles in normal serum or in saline; nor did they appear on the third stage juveniles on incubation in immune sera. Apparently the excretory-secretory products of the fourth stage juveniles of O. columbianum serve as antigen and play an important role in the stimulation of antibodies in the host.

2. Inactivation of the immune serum did not destroy the precipitin type of antibody, nor was it affected when the immune animals had been treated with cortisone.

3. Immune serum from animals receiving multiple infections showed a higher antibody titre.

4. The possible way in which the antibody acts on the fourth stage juveniles, causing their immobilisation and subsequent death, is discussed.

In 1927 and 1928 Hiraishi published some observations which he had made on Ascariasis in swine in the absence of Vitamin A. He claimed that he had been successful in overcoming the resistance of the pigs to the human strain of Ascaris lumbricoides by lowering the vitamin A content of the diet and that he was able to produce much heavier infestations with Ascaris lumbricoides of swine origion in A-avitaminosed pigs. As all other factors were apparently controlled, he draws the conclusion that vitamin A has a direct bearing on the susceptibility of the pig to infestation with round worms. Unfortunately these publications are not readily available in England and only summaries of results have been available to the present writer. But from the data given and in comparison with the effect of the vitamins on Ascaridia (Ackert et alia, 1929 and 1931 a & b) and on hookworm (Foster & Cort, 1931 and 1932), these conclusions would seem to be justified.

A brief description has been given in an earlier paper (Goodey, 1943) of damage to tulip bulbs caused by the stem and bulb eelworm, Anguillulina dipsaci. In April, 1944, an opportunity arose, through the good offices of Mr. J. Oldnall Page, of Spalding, Lincs., of visiting a field in his district, in which eelworm-affected tulips were growing. Two of the varieties inspected were in flower and the other two were in an advanced bud condition. All four varieties exhibited marked symptoms of attack, and in the case of two of them in which there were a considerable number of plants, the damage caused to the blooms would entail a distinct financial loss to the grower. The largest planting consisted of the variety “ Rijnland,” the next largest was the variety “Wonderful.” In addition to these there were smaller plantings of “ William Copland ” and “ Mrs. Farncombe Sanders.” In all four varieties evidences of attack were apparent on leaves, stems and flowers and, in general, the writer can confirm the findings of Chitwood and Machmer (1942) on the symptoms manifested by the growing plant. They mention longitudinal splitting of leaf, flower-stem and corolla. It may be well, however, to attempt a more detailed description of the chief symptoms and types of lesion shown by affected plants: see also the two photographs accompanying this paper.